Acres of Cropland Converted to Developed Land, 1982-1997 (dot map)

Description

This dot map shows acres of cropland that have been converted to Developed land from 1982 to 1997 by 8-digit hydrologic unit. Developed land includes urban and built-up areas and rural transportation land. Each dot represents 1,000 acres of cropland developed. Areas with 95% or more federal land are shaded gray. There were 7.1 million acres of Cropland in 1982 converted to Developed Land in 1997.

Cautions for this Product:
This map may not be used for site-specific information. The data have been aggregated such that dots are placed randomly by 8-digit hydrologic units within each state. Data are not collected on Federal land. Data are not available for Alaska or the Pacific Basin. Data for Puerto Rico and the U.S. Virgin Islands are aggregated by 6-digit hydrologic unit. This map does not show net change, acres of developed land converted to cropland are not included.

Sources

Source:National Resources Inventory, 1997Distributor: USDA-NRCS-RIADReliability:
NRI sample data are generally reliable at the 95% confidence interval for state and certain broad substate area analyses. Generally, analyses that aggregate data points by smaller geographic areas and/or more specific criteria result in fewer data points for each aggregation and therefore less reliable estimates. NRI maps reflect national patterns rather than site- specific information.

Layers

Aggregate Layer: Cross of State with 8 Digit Hydrologic Units and Federal Land Other Layers Displayed: States, Rivers

Definitions

Built-up land:
See urban and built-up land. [NRI-97]

Cropland:
A Land cover/use category that includes areas used for the production of adapted crops for harvest. Two subcategories of cropland are recognized: cultivated and noncultivated. Cultivated cropland comprises land in row crops or close-grown crops and also other cultivated cropland, for example, hayland or pastureland that is in a rotation with row or close-grown crops. Noncultivated cropland includes permanent hayland and horticultural cropland. [NRI-97]

Federal land:
A land ownership class designating land that is owned by the Federal Government. It does not include, for example, trust lands administered by the Bureau of Indian Affairs nor Tennessee Valley Authority (TVA) land. No data are collected for any year that land is in this ownership. [NRI-97]

Land cover/use:
A term that includes categories of land cover and categories of land use. Land cover is the vegetation or other kind of material that covers the land surface. Land use is the purpose of human activity on the land; it is usually but not always related to the land cover. The NRI uses the term (land cover/use) to identify the categories that account for all the surface area in the United States [BS-1982; NRI-97]

Rural transportation land:
A Land Cover/Use category which consists of all highways, roads, railroads and associated rights- of-way outside urban and built-up areas; including private roads to farmsteads or ranch headquarters, logging roads, and other private roads, except field lanes. [NRI-97]

Urban and built-up areas:
A Land Cover/Use category consisting of residential, industrial, commercial, and institutional land; construction sites; public administrative sites; railroad yards; cemeteries; airports; golf courses; sanitary landfills; sewage treatment plants; water control structures and spillways; other land used for such purposes; small parks (less than 10 acres) within urban and built-up areas; and highways, railroads, and other transportation facilities if they are surrounded by urban areas. Also included are tracts of less than 10 acres that do not meet the above definition but are completely surrounded by Urban and Built-up land. Two size categories are recognized in the NRI: (i) areas 0.25 to 10 acres, and (ii) areas greater than 10 acres. [NRI-97]